Railway-traffic-controlling apparatus



' March 31. 1925. 1,531,864

R. A. M cANN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed'sepnp, 1924.

Patented Mar. 31, 1925 V UNITED STATES 1 Ismael PATENT o e-rice."

RONALD A. MGCANN, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR- TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

nnILway trnsrrro-oonrnomrne APPARATUS.

Application filed September 9, 1924. Serial N0. 736,682.

To all whom it may concern:

Be it known that I, RONALD A. MCCANN,

a citizen of the United States, residing at Swissvale, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway- Traific-Controlling Apparatus, of which the following is a specification.

My invention relates to railway trailic controlling apparatus and particularly to apparatus of the type comprising train carried governing means controlled by energy received from the trackway.

More particularly, my invention relates to the trackway portion of such apparatus.

I will describe one form and arrangement of trackway apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatical view showing one form of trackway apparatus embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track over which traflic normally moves in the direction indicated by the arrow. These rails are divided by means of insulated joints 2, into a plurality of track sections of which only one full section AB is shown inthe drawing.

Section AB is provided with a switch 4 leading into a branch track D. The rails 3 and 3 of a portion of this branch track are separated, by means of insulated joints 2 into a track section EF extending from the switch 4 to the fouling point F. It will be plain that with this arrangement one rail 3 of section El3 is isolated, and the other rail 3* is electrically connected with rail 1 of section AB by means of the frog 4 associated with the switch 4:.

Section AB is supplied with alternating track circuit current by a track transformer T having a secondary 6 constantly connected, through impedance 7, with. the rails adjacent the exit end of the section. The primary 8 of this transformer is constantly supplied with alternating current from some suitable source such as an alternator M, over line wires 5 and 5 A track relay R is connected with the rails adjacent the rear end of the section and is responsive to current supplied to the section by transformer T. Also located adjacent point B is an auxiliary relay J, the function of which will be explained hereinafter.

Located adjacent point A is a trackway signal S of any suitable form and here illustrated as a two-position semaphore signal. This signal is controlled, by means forming no part of the present disclosure and omitted from the drawing for the sake of simplicity, so that when the section to the left of point A' is occupied signal S indicates stop and when this section is unoccupied the signal indicates proceed.

A second signal S is located adjacent point B for governingtraflfic through Sec tion AB and is controlled by means to be described hereinafter.

Means are also provided for supplying to the section AB a train controlling loop current which flows through the rails of the section in parallel. For this purpose I provide an impedance 13 connected across the rails adjacent the forward end of the section and a similar impedance 140011- nected across the rails adjacent the rear end of the section. The connections for the loop circuit are made to the mid points of these iinpedances. The immediate source of loop current is a loop transformer L having a primary 10 constantly supplied with alternating current from line wires 5. and 5 'lVhen signal S indicates proceed the loop circuit for-section A-B may be traced from secondary 90f transformer L, throughwwire 11, circuit controller K operated by signal S wire '12, impedance 13, through both rails of section ALB in parallel to impedance 14, thencethrough wire 15, winding mechanism of signal S over front contact 18. of relay J and front contact 19 of relay R as will beapparent from the draw ing,1 and signal S will then indicate proceec. Y

l/Vhena train occupies any portion of section A-.B, relay R will be de-energized and signal S? will, indicate stop.

If a train occupies any portion of section EF, that is any portion of branch track D between the fouling point and the switch, the wheels and axles of such train Will connect rail 3 with rail 3* and hence with rail 1 of section AB. Under this condition loop current will flow as before from secondary 9 or transformer L, through circuit controller K and impedance 13, but from the rail 1 of section AB, the loop current will flow to rail 3 through the wheels and axles of the train occupying section EF, and through wire 17 back to transformer L. It will be plain that under these conditions loop current is shunted away from that portion of section A-B in the rear of switch 4 and from relay J Which then becomes deenergized and causes signal S to indicate stop. r p

It should here be pointed out that the trackway apparatus herein shown and described is suitable for cooperation with train carried governing ineclianism s'o arranged that when loop current is being supplied to the portion of track occupied by the train the governing mechanism displays a less restrictive indication such as proceed, whereas when the supply of such loop current discontinued the governing mechanism displays a more restrictive indication, su'ch asa stop indication,

As shown in the drawing, signals is at proceed and sections A-B' and EF a're both unoccupied, loop current is therefore supplied to section AB throughout its length, relays R and J are energized, and signal S indicates proceed; If, under these conditions, a train moving in the direction indicated by the arrow enters? section A 13 the governing mechanism will display a proceed indication as the train passes through the section.

I will now assume that a tr'ain occupies section E-F. Loop current will then be supplied to section A-B betweenpoint A and switch 4 but not between switch 4 and point B. Relay J will be de-energized and signal S will indicate stop. If new train enters sect-ion lid-13 at point B, stop indication will be received on the train;

If a train moving in the direction of the arrow be between point A and switch 4 under a proceed indication and a second train moves into section E-F, no change will result in the indication received on the first train because the presence of a train in section E-F has no effect upon the loop current between point A and switch 4.

Que feature of my invention is that a train on branch track D in such position as to render it unsafe for trains to proceed along section A-B pastswitch 4, causes signal S to indicate stop, and also causes a stop indication to be received, on a: train insection AB approaching the switch.

Although I have herein shown and described only one form and arrangement of tra'ckway apparatus embodying my invention, itis understood that various changes and modifications may bemade therein within the scope of'the appended clainiswithout departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track having a branch track connected therewith by means of a switch, means for supplying track circuit current to said section, means for supplying said section: also with train controlling loop current, and means effective when a train occupies said branch track between the fouling pointand said switch for discontinuing the supply of such loop current to a portion of said section.

2. In combination, a section of railway track having branch track connected therewith by means of a switch, means for supplying track circuit current to said section, means for supplying said section also with train controlling loop current, and meanseffective when a train occupies said branch track between the fouling point and said switch for discontinuing the supply of such loop current to the portion of the section in the rear of said switch; I

3. In combination, a section of railway track having a branch track connected therewith by means of a switch, insulated joints for isolating a rail of said branch track between said switch and the fouling point the other rail of the branch track being electrically connected with one rail of said section, and aloop circuit forsaid section. including a source of alternating current, the rails of said section in parallel, and the isolated rail of said branch track in series. v

4. In combination, a section of railway track having a branch track connected therewithby means of a'switch, insulated joints for isolating a; rail of said branch track between said switch and the fouling point, theother rail er the branch track be ing' electrically connected with one rail of said section, a source of alternating'curi'ent having one terminal connected with said one rail and the other terminal connected with the isolated rail of said branch track, and means for connecting said isolated rail with said one rail adjacent the rear end or said section. I

5. In combination, a section of railway track having a branch track connected therewith by means of a switch, insulated joints for isolating a rail of said branch track between said switch and the fouling point, the other rail of the branch track'being electrically connected with one rail of said section, a relay; a source of alternating current having one terminal connected with said one rail and the other terminal connected with the isolated rail of said branch track, means including a winding of said relay for connecting said isolated rail with said one rail and a trackway signal controlled by said relay for governing trafiic through said section.

6. In combination, a section of railway track having a branch track connected therewith by means of a switch, means for supplying train controlling loop current to the rails of the section in parallel, and means effective when a train occupies said branch track between the fouling point and said switch to shunt loop current away from the rails of said section in the rear of the switch by means of the wheels and axles of such train.

7. In combination, a section of railway track having a branch track connected therewith by means of a switch, insulated joints for isolating a rail of said branch track between said switch and the fouling point, the other rail of the branch track being electrically connected with one rail of said section, a trackway signal for governing trafiic in advance of said section, a circuit controller operated by said signal, a first impedance connected across the rails adjacent the forward end of said section, a second impedance connected across the rails adjacent the rear end of said section, and

also connected with the isolated rail of said branch track, a source of train controlling loop current having one terminal connected with said isolated rail, and means including said circuit controller for conneotin the remaining terminal of said source with such isolated rail.

In testimony whereof I ailix my signature.

RONALD A. MoOANN. 

